andrew.w.kaylor added inline comments.
================
Comment at: clang/docs/UsersManual.rst:1388
- * ``precise`` Disables optimizations that are not value-safe on
floating-point data, although FP contraction (FMA) is enabled
(``-ffp-contract=fast``). This is the default behavior.
* ``strict`` Enables ``-frounding-math`` and
``-ffp-exception-behavior=strict``, and disables contractions (FMA). All of
the ``-ffast-math`` enablements are disabled.
----------------
lebedev.ri wrote:
> I'm confused. Where in this patch the `This patch establishes the default
> option for -ffp-model to select "precise".` happens? LHS of diff says it is
> already default
The comments said that it was the default, but the actual default was something
that didn't quite match any of the fp-models -- precise but with fp contraction
off.
================
Comment at: clang/lib/Driver/ToolChains/Clang.cpp:2548
DenormalFPMath = DefaultDenormalFPMath;
FPContract = "";
StringRef Val = A->getValue();
----------------
I think this always gets changed to fast, on, or off below, but making it empty
here looks wrong.
================
Comment at: clang/lib/Driver/ToolChains/Clang.cpp:2661
// the FPContract value has already been set to a string literal
// and the Val string isn't a pertinent value.
;
----------------
Does this mean that "-ffp-model=precise -ffp-contract=off" will leave FP
contraction on? That doesn't seem right.
================
Comment at: clang/lib/Driver/ToolChains/Clang.cpp:2769
DenormalFPMath != llvm::DenormalMode::getIEEE() &&
- FPContract.empty())
+ (FPContract.equals("off") || FPContract.empty()))
// OK: Current Arg doesn't conflict with -ffp-model=strict
----------------
We should never get here with FPContract empty.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D74436/new/
https://reviews.llvm.org/D74436
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